WASHINGTON (AP) — In President Donald Trump’s Washington, matters of war and peace are decided in 280-character bursts. It’s up to John Bolton to massage them into a foreign policy.

The mustachioed national security adviser developed a reputation as a bureaucratic bulldozer through more than three decades in and out of government. But the wrangling over Trump’s decision to pull troops out of Syria demanded a new skill — the ability to dramatically redraft the president’s policy without provoking a hint of protest from the commander in chief.

When Trump announced on Dec. 19 that he saw no need for U.S. troops to remain in Syria, senior U.S. officials expected the Trump-ordered withdrawal to be completed within a month. Aides, lawmakers and overseas allies were beside themselves with concern that the U.S. was betraying its Kurdish allies in the fight against the Islamic State and ceding influence in the region to Iran and Russia. Secretary of Defense Jim Mattis quit in protest.

But one month after Trump declared that U.S. forces were “coming back now” and White House press secretary Sarah Huckabee Sanders said the administration had “started returning United States troops home,” the drawdown of U.S. troops has only just begun. The explanation, senior White House officials said, is the behind-the-scenes effort by Bolton.

Bolton was always an unlikely pick to be Trump’s third national security adviser, with a world view seemingly ill-fit to the president’s isolationist “America First” pronouncements. He’s espoused hawkish foreign policy views dating back to the Reagan administration and became a household name over his vociferous support for the Iraq War as the U.S. ambassador to the U.N. under George W. Bush. Bolton even briefly considered running for president in 2016, in part to make the case against the isolationism that Trump would come to embody.

Yet he earned Trump’s ear in part through his frequent appearances on Fox News, the president’s favored network. And despite the president’s aversion to his bushy mustache, the two have formed a close relationship since Bolton took over at the National Security Council in April.

“Frankly, what I have said in private now is behind me,” Bolton told Fox News last year just after joining the White House. “The important thing is what the president says and the advice I give him.”

Longtime associates credit Bolton with a keen ability to manage-up to the president — a key differentiator between Bolton and his predecessor, H.R. McMaster, an Army general whose professorial tones grated on Trump.

That doesn’t mean that Bolton was on board with Trump’s impulsive policy announcement on Syria, officials said. Rather than go public with the same concerns aired by Mattis and others, though, Bolton quietly set out on a monthlong revision of Trump’s order, leading to critical adjustments that the administration, at least publicly, is loathe to acknowledge.

“A lot of the press coverage about the decision on Syria missed what the president had in mind,” Bolton insisted in Jerusalem this month, overlooking the fact that many of Trump’s own aides were also in the dark. His role, Bolton said, “is to help elaborate what the president’s conditions are and what he expects.”

He and Trump have harshly pushed back on any notion of a policy reversal. White House aides cast Bolton’s role as merely “elucidating” or “clarifying” the president’s initial order.

“No different from my original statements,” Trump tweeted on Jan. 7.

In reality, there were key changes. One month in, materiel has been removed from northeastern Syria, but troops remain. In the war-torn country’s south, 200 U.S. service members serving in al-Tanf are now remaining in place indefinitely as a check against Iran — a step sought by Israel. And in a trip to the Middle East this month, Bolton announced new “conditions” on the withdrawal, including demanding assurances from Turkey it won’t attack Kurdish fighters in Syria.

The pace of the planned withdrawal was dramatically slowed, first, after Trump’s three-hour December visit to Iraq to meet with U.S. commanders in which they argued that they, not allies, were best positioned to destroy the last vestiges of the Islamic State’s territorial caliphate in Syria. Then came concerns about the fate of the Kurds, who face assault from Turkey, which considers them a terrorist group, and Iranian regional influence.

According to seven administration officials, Bolton’s influence was central to the “reinterpretation” of Trump’s initial order and convincing the stubborn commander in chief to go along with it. White House aides maintained that the two have a strong relationship in part because Bolton has tried not to draw attention to the changes. The officials spoke on the condition of anonymity to describe Bolton’s role and the administration’s policy thinking.

It was a sign of Bolton’s outsized role in foreign policy that when he traveled to Israel and Turkey earlier this month to clarify the policy, he brought along a contingent of press aboard a modified Boeing 757 of the type typically used by the vice president and secretary of state. It was the first trip by a national security adviser to include reporters in recent memory.

Bolton, who was briefly considered by Trump for the role of U.N. ambassador, was clearly in his element, taking in cultural sites with allies and soberly delivering dire warnings to foes. Unafraid to stir the pot, he didn’t seem to mind a bit when Turkish President Recep Tayyip Erdogan very publicly accused him of making “a very serious mistake” in saying the U.S. would insist that Turkey refrain from attacking its Kurdish partners.

The episode led Erdogan to scrub plans to meet with Bolton and sent relations between the NATO allies to a fresh low.

Bolton’s approach has drawn some charges of heavy-handedness from other corners of the administration, as some Trump loyalists argue he’s using the NSC to implement his own priorities over the president’s. Some in the White House were shocked that the NSC took hours to explain Trump’s Syria decision, chalking it up to Bolton’s objection to the policy. But Bolton allies contend he’s fulfilling the president’s wishes in fleshing-out the president’s top-line decisions, and White House officials insist reports of bad blood between the two are misguided.

Bolton “works every day to advance President Trump’s national security strategy to keep our country safe and secure,” Vice President Mike Pence said in a statement. “Ambassador Bolton is a strong leader who is respected by our allies around the world. He understands that America First means strong U.S. leadership is critical on the world stage and it is my great honor to serve with him.”